Moldable wire thread insert, method for its production, component with a moldable wire thread insert as well as a method for its production

ABSTRACT

A moldable wire thread insert  1  for reinforcing a screw-in opening of a component has the following characteristics: a cylindrical spiral  20  made of a helically, wound wire  10,  the neighboring coils  30  of which are arranged such that a closed cylindrical spiral wall  22, 24  is present, while at least one end of the cylindrical spirals  20  has a fastening flange  40,  which extends radially outwards over the cylindrical spiral wall  22, 24  and with which the wire thread insert  1  is anchorable in the component and/or one end of the cylindrical spiral  20  is designed in a planar manner in order to form an even axial front surface of the cylindrical spiral  20.

1. FIELD OF THE INVENTION

The present invention relates to a moldable wire thread insert forreinforcing a screw-in opening of a component. Furthermore, the presentinvention is aimed at a method for producing the moldable wire threadinsert as well as a component with this moldable wire thread insert.Moreover, the present invention relates to a production method for acomponent with this moldable wire thread insert.

2. BACKGROUND OF THE INVENTION

Wire thread inserts are generally known in the state of the art. Thesewire thread inserts are inserted into bore holes with internal threadsin order to reinforce these bore holes. This is necessary for examplewhen a screw to be fastened is made of a harder material than thecomponent in which the bore hole is arranged and thus relaxation effectsmust be compensated for in the component material. These wire threadinserts are wound such that they have a greater inner diameter than thatof the thread to be formed later in the bore hole. Moreover, the coilsof the cylindrical spirals of the wire thread insert in the axialdirection are separated from each other similar to a spring. In aspring-pretensioned state, the wire thread insert is inserted into athreaded bore hole so that it fastens itself in the threaded bore holedue to its effort to expand itself again. Such wire thread inserts areknown for example from international patent application WO 2005/124165A1.

Furthermore, wire thread inserts are known, in whose cylindrical spiralsneighboring coils lie next to each other, so that the inner wall of thecylindrical spiral already provides a standard thread. The individualcoils of the cylindrical spiral are designed sharp-edged on the radialouter wall of the cylindrical spiral so that the cylindrical spiral hasa self-cutting, cylindrical outer wall. In the case of wire threadinserts formed in this manner, which are for example disclosed ininternational patent application WO 2007/147196 A1, it is no longerrequired to insert the wire thread insert into a prefabricated thread ofa bore hole. Rather the wire thread insert cuts itself into the innerwall of the bore hole and is fastened in the component in this manner.

U.S. Pat. No. 2,672,070 and EP 1 046 446 B1 describe methods in whichwire thread inserts are positioned in a component mold in order to moldthem into the component during component production. The components aremade for example of metal or plastic.

The types of wire thread inserts described above as well as thedifferent methods for their use in a component bore hole have thedisadvantage that, in the course of use of the component opening withwire thread insert, it loosens in the component opening and no longersufficiently supports the screw fastened in it or a similar fasteningelement. In the worst case, the fastening element is no longer held inthe component opening and can no longer fulfill its function. As aconsequence, an exchange of the component or an enlargement of thecomponent opening and an insertion of a new wire thread insert as wellas the use of a fastening element with an adjusted diameter arerequired. This is complicated and partially constructively impossible.Furthermore, it is disadvantageous that such a retrofitting results instandstill times e.g. of a constantly used machine.

It is thus the object of the present invention to provide a moldablewire thread insert as well as a method for its production, whichovercomes the disadvantages of the state of the art. Moreover, a methodfor producing a component with this molded wire thread insert should beprovided.

3. SUMMARY OF THE PRESENT INVENTION

The above objects are solved through a moldable wire thread insert inaccordance with claim 1, a component with this moldable wire threadinsert in accordance with claim 14, a production method for a moldablewire thread insert in accordance with claim 15, a production method fora component with this molded wire thread insert in accordance with claim25 as well as through a winding spindle for producing the moldable wirethread insert in accordance with claim 28. Advantageous embodiments andfurther developments of the present invention arise from thedescription, the drawings and the attached claims.

The moldable wire thread insert according to the invention forreinforcing a screw-in opening of a component has the followingcharacteristics: a cylindrical spiral made of a helically, wound wire,the neighboring coils of which are arranged such that a closedcylindrical spiral wall is present, while at least one end of thecylindrical spiral has a fastening flange, which extends radiallyoutwards over the cylindrical spiral wall and with which the wire threadinsert is anchorable in the component and/or one end of the cylindricalspiral is designed in a planar manner in order to form an even axialfront surface.

The moldable wire thread insert according to the invention is formed bya wire spiral wound on block. In this case, wound on block means thatneighboring wire coils of the spiral are adjacent to each other suchthat an approximately closed spiral wall of the moldable wire threadinsert is formed. In this manner, the wire coils form a permanentsocket. The adjacency of the neighboring coils of the cylindrical spiralensures that during a molding of the wire thread insert for example intoa plastic component during injection molding no plastic can penetratethrough the spiral wall into the inside of the wire thread insert.However, sufficient anchoring of the moldable wire thread insert in theplastic component is simultaneously ensured. This takes place on onehand via the radial cylindrical outer wall of the wire thread insert aswell as via the fastening flange according to the invention on at leastone end of the cylindrical spiral. This fastening flange projectsoutwards radially compared to the cylindrical spiral and is almostcompletely surrounded by the material of the component. In this manner,the fastening flange is anchored in the material of the component andprevents a twisting or other shift of the moldable wire thread insert inthe component. In accordance with preferred embodiments of the presentinvention, the fastening flange is provided on only one or two ends ofthe cylindrical spiral. If the fastening flange is arranged on thecylindrical spiral on only one side, it also serves as a unique sortcriterion for the automatic handling of the moldable wire thread insert.

It is preferred that the fastening flange comprises at least one flangecoil of the wound wire, which has a reduced, preferably no, slopecompared to the cylindrical spiral. In accordance with a furtherpreferred embodiment, the fastening flange comprises at least two coilsof the wound wire lying above each other in the radial direction of thecylindrical spiral.

The fastening flange of the moldable wire thread insert according to theinvention consists of the same wound wire as the other cylindricalspiral. Since this wound wire on the end of the cylindrical spiral isjust wound differently than the other wire thread insert, the wirethread insert according to the invention can be produced in an easymanner. The size of fastening flange is variable depending on thecomponent material in which the moldable wire thread insert needs to befastened. For this purpose, two coils lying above each other in theradial direction of the cylindrical spiral or also several coils arearranged for the formation of the fastening flange. The radially outercoil of the fastening flange is designed at least partially, preferablycompletely, circumferentially around the spiral.

In accordance with a further preferred embodiment of the presentinvention, the fastening flange comprises a first coil, which extendsalong a circumferential segment of the fastening flange starting at theend of the cylindrical spiral over an angle of at least 180°, preferably180° to 270° and more preferably of 180° to 360°. In accordance withthis embodiment, the first coil of the fastening flange is arrangedoutwards radially with respect to the circumference of the cylindricalspiral. However, this first coil does not extend along the entirecircumference of the cylindrical spiral, i.e. over a circumferential orcircular segment of 360°. Instead, the first coil runs along acircumferential segment of the fastening flange, which extends over anangle of at least 180°. This circumferential segment outwards radiallyrelated to the cylindrical spiral already ensures sufficient anchoringof the moldable wire thread insert during molding in a component to beproduced. Moreover, a thusly designed fastening flange can also be usedas sort criterion during the handling of the moldable wire threadinserts.

In accordance with a further preferred embodiment of the presentinvention, the fastening flange comprises a complete first coil and asecond coil, which extends along a circumferential segment of thefastening flange starting at the end of the first coil over an angle ofat least 180°, preferably 180° to 270° and more preferably of 180° to360°. In accordance with this preferred embodiment, the second coil ofthe fastening flange is designed similarly to the first coil of thefastening flange described above, only that it connects to a completelycircumferential first coil of the fastening flange.

In order to provide another anti-twist protection for the moldable wirethread insert as an addition to the fastening flange, preferably thecylindrical spiral wall on a radial outside has at least one grooverunning in the longitudinal direction of the cylindrical spiral,preferably a plurality of grooves. A cross-section of the wound wire ofthe wire thread insert is also preferably equipped outwards radiallywith respect to the cylindrical spiral with an angle contour with twoflanks, which encloses an angle <60°, preferably an angle between 30°and 40°. With the help of this acute-angled contour on the outside ofthe cylindrical spiral, which anchors itself in the component material,sufficient resistance of the wire thread insert against shear loading iscreated depending on the size of the flank angle. This supports thefastening of the wire thread insert and its hold in the component.Moreover, radial tension on the wire thread insert is reduced by thisshape. If the moldable wire thread insert has a preferred standardthread on its inside, then the wound wire has an asymmetricalcross-sectional profile due to the angle contour anchoring itself in thematerial on the radial outside of the cylindrical spiral.

In accordance with a further preferred embodiment, the end of the wirethread insert, which is arranged opposite the end with fastening flange,has a radially inwards projecting tang or a free through hole opening.In accordance with different alternatives of the preferred constructionof the wire thread insert, this tang is removable or not. The tangsupports a positioning of the wire thread insert on a pin during theproduction of a component with this moldable wire thread insert (seebelow).

The present invention also comprises a component consisting of plasticor metal, in which a moldable wire thread insert is molded in accordancewith one of the alternatives described above.

Moreover, the present invention comprises a production method of amoldable wire thread insert for reinforcing a screw-in opening of acomponent. The production method comprises the following steps: windingof a wire into a cylindrical spiral with a diameter such thatneighboring coils of the cylindrical spiral have a first slope and forma cylindrical spiral wall and creation of a fastening flange protrudingradially outwards over the spiral wall on at least one end of the spiralor planar grinding of the cylindrical spiral on at least one end of thespiral, preferably cutoff grinding of the cylindrical spiral. Thefastening flange is preferably created by the winding of at least onecoil of the spiral without slope on one end of the spiral. It isfurthermore preferred that at least two coils of the wound wire lyingabove each other in the radial direction are wound in order to form thefastening flange.

In a further embodiment of the aforementioned method, a winding of atleast one coil of the spiral takes place on one end of the spiral with aslope reduced with respect to the first slope in order to form thefastening flange. The wire thread insert to be produced, which has thecylindrical spiral in one area and the at least one fastening flange inthe end area of the cylindrical spiral, is wound with different slopesof the wire in the area of the fastening flange and in the area of thespiral. These different slopes are created among other ways in thatduring the winding a differently strong offset of the wire to be fed isused in relationship to the already wound wire thread insert. Coils withdifferently strong slopes in the area of the spiral and in the area ofthe fastening flange occur in this manner.

In accordance with a further embodiment of the present method, thewinding of the fastening flange occurs such that the fastening flangehas a greater diameter than the spiral. The end of the spiral preferablycomprises at least two coils of the wound wire approximately lying aboveeach other in the radial direction of the cylindrical spiral. It is alsopreferred to wind coils of the fastening flange over a circumferentialsegment, the shape of which was already described above.

It is also preferred to wind the wire onto a winding spindle, whereinthe winding spindle comprises a first cylindrical area for the windingof the cylindrical spiral and an area second compared to the cylindricalarea expanded in the radial direction for winding the fastening flange.

A winding spindle, which has two different areas when seen from theaxial direction, is preferably used for the production of the moldablewire thread insert. In a first cylindrical area of the winding spindle,a thread is provided in order to wind onto it the cylindrical spiral ofthe later wire thread insert. A second area connects to this firstcylindrical area, with the help of which the fastening flange is wound.In accordance with a first embodiment, the second area forms a ledge incomparison to the first area so that, during the winding, the wire iswound against this ledge. In accordance with a second embodiment, thesecond area is expanded in the radial direction in comparison with thefirst area so that, during the winding, the wire is wound on thisexpanded area. With respect to the expanded area of the winding spindle,it is also preferred that it expands constantly or gradually. Based onthis shape of the winding spindle, the geometry of the fastening flangeand/or the arrangement of the coils of the fastening flange areimpacted.

It is furthermore preferred to wind the wire on the winding spindle suchthat a longitudinal axis of the winding spindle in the winding directionof the wire thread insert and a wire feed direction of the wire to bewound make up an angle β≧90°. With the help of this targeted angularadjustment between the wire feed direction and the longitudinal axis ofthe winding spindle in the winding direction, the wire of the wirethread insert to be produced is preferably provided with innermechanical tensions. After the unspindling of the produced wire threadinsert from the winding spindle, these embossed mechanical tensionsensure that the moldable wire thread insert is pulled together in theaxial direction such that neighboring windings lie against each other.This applies preferably both for the coils of the cylindrical spirals aswell as for the windings of the fastening flange. The moldable wirethread insert is thereby sealed outwardly so that no plastic can getinside the moldable wire thread insert in the case of a later molding ofthe moldable wire thread insert for example in the plastic. Moreover, athread similar to a threaded bushing is designed on the inside of thecylindrical spiral. This thread is preferably a metric or imperialthread.

It is also preferred to shift the winding spindle and the feed positionof the wire to be fed relative to each other with different values,while the wire is wound onto the first and the second area of thewinding spindle. Also this different offset of the winding spindle inits longitudinal direction in relation to the feed direction orrespectively the feed position of the wire to be wound also impacts howneighboring coils of the cylindrical spiral and of the fastening flangelie against each other after an unspindling of the produced wire threadinsert.

It is furthermore preferred to produce the moldable wire thread insertwith a radially inwards sticking tang with respect to the cylindricalspiral. For this purpose, the production method preferably comprises ahooking in of the wire to be wound into a notch of the winding spindleand creation of the radially inwards sticking tang on the end of thespiral facing away from the flange onto the winding spindle through thewinding up of the wire.

Furthermore, the present invention comprises a production method for acomponent with a molded wire thread insert, which has a cylindricalspiral formed from a helically, wound wire, of which at least one endcomprises a fastening flange, which extends radially outwards over thecylindrical spiral. The component to be produced is made of plastic,metal or other suitable material. In the case of metal components, lightmetals such as aluminum, magnesium or the like are preferably used. Theaforementioned production method has the following steps: Thepositioning of the wire thread insert on a pin, arrangement of the pinwith wire thread insert in a mold such that the fastening flange isarranged adjacent to a component surface after the demolding of thecomponent from the mold, filling of the mold with metal or plastic anddemolding of the component with wire thread insert from the mold.

In order to be able to suitably position the wire thread insert, it ispreferably spindled onto the pin, which has a thread fitting the wirethread insert for this purpose. In accordance with another alternative,it is preferred to mount the wire thread insert on the pin without athread. The pin with wire thread insert is then arranged in the mold andfastened so that, during the introduction of the material of thecomponent, the positioned wire thread insert retains its position.

Should the wire thread insert have a radially inward protruding tang onthe end of the wire thread insert facing away from the fastening flangeas a positioning aid, it serves for example as a stop during mounting ofthe wire thread insert on the pin without thread.

Furthermore, the present invention comprises a winding spindle forwinding a moldable wire thread insert, which has the followingcharacteristics: a first cylindrical area with a thread and a secondarea, which is expanded in the radial direction compared to the firstarea, so that the fastening flange of the moldable wire thread insert isproducible with the help of the second area. In accordance with afurther embodiment of the winding spindle, the second expanded area isalways or gradually expanded compared to the first area or it isdesigned as a single level and represents a ledge compared to the firstcylindrical area. The second area is thus preferably arranged at anangle of 90° to 120° to the longitudinal axis of the winding spindle(70).

In accordance with a preferred embodiment, a notch is provided on oneend of the first cylindrical area, in which a wire to be wound isfastened in order to form a radially inward sticking tang during thewinding of the wire thread insert.

4. SHORT DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The preferred embodiments of the present invention are explained ingreater detail in reference to the accompanying drawing. They show in:

FIG. 1 a perspective view of a preferred embodiment of a wire threadinsert with fastening flange,

FIG. 2 a side view of the embodiment in FIG. 1,

FIG. 3 a cut representation with sectional enlargement of a preferredwire thread insert with surface-ground ends,

FIG. 4 a further sectional representation of a wire thread insert,

FIG. 5 a schematic representation of a preferred cross-sectional shapeof the coil of the wire thread insert from FIG. 1,

FIG. 6 a schematic representation of the design of the outer wall of thewire thread insert from FIG. 1,

FIG. 7 a preferred perspective representation of a moldable wire threadinsert with two fastening flanges,

FIG. 8 the preferred embodiment from FIG. 7 in a cut representation,

FIG. 9 a top view of a preferred wire thread insert with fasteningflange and screw lock,

FIG. 10 a side view of the embodiment in FIG. 9,

FIG. 11 a preferred production of the wire thread insert with the helpof a cutoff wheel,

FIG. 12 a schematic representation of a preferred winding spindle,

FIGS. 13A-C a schematic representation of a preferred molding of thewire thread insert with, without and with two fastening flanges in onecomponent,

FIG. 14 a schematic representation of a preferred molding of the wirethread insert with fastening flange in one component,

FIG. 15 a flow chart of a preferred production of wire thread insertsand

FIG. 16 a flow chart in accordance with a preferred production of acomponent with wire thread insert.

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a first preferred embodiment of a moldable wire threadinsert 1. The wire thread insert 1 serves to reinforce screw-in openingsof a component in order to avoid a mechanical overload of a componentmaterial during screwing in of a fastening element. For this purpose,the wire thread insert 1 comprises a cylindrical spiral 20. Thecylindrical spiral 20 is spirally wound during the production of thewire thread insert 1 from a wire 10 (S1). The coils 30 wound with acertain slope of the cylindrical spiral 20 form a standard thread on theradial inner wall 22 of the cylindrical spiral 20. In accordance withdifferent preferred embodiments, this standard thread is a metric or animperial thread. The thread designed on the radial inside 22 of thecylindrical spiral 20 is determined through a cross-section 50 of thewire 10 and through the arrangement, in particular the slope, of theneighboring coils 30.

Since the wire thread insert 1 is moldable into a component to beproduced, the cylindrical spiral 20 comprises a closed cylindricalcircumferential spiral wall. In this manner, the wire thread insert 1 issurrounded by the component material during the filling (D) of a mold 90during the component production without the component material gettinginside the cylindrical spiral. In order to form a closed cylindricallycircumferential spiral wall of the spiral 20, the neighboring coils 30are arranged according to different embodiments of the wire threadinsert 1. In accordance with a first embodiment, the wire 10 has across-section 50 shaped in any manner and the possible interspacesbetween neighboring coils 30 are sealed by means of a coating or sealingmass 80 (see FIG. 4).

The sealing mass 80 is sprayed on for example during the production ofthe wire thread insert 1 or applied through dipping of the wire threadinsert 1. It is thus also preferred to provide the cylindrical spiral 20on the inside 22 and the outside 24 with the sealing mass 80.

In accordance with a further preferred embodiment of the presentinvention, the cross-section 50 of the wire 10 of the wire thread insert1 comprises a thread area 52 as well as an anchor area 54 (see FIG. 3).The thread area 52 and the anchoring area 54 are connected with eachother via axial front surfaces 56 relating to the longitudinal axis ofthe cylindrical spiral 20. The front surfaces 56 are preferably designedplanar so that opposite-lying front surfaces 56 of neighboring coils 30lie against each other in a sealing manner. This is emphasized in thesectional enlargement in FIG. 3.

In accordance with an embodiment shown in FIG. 5, the opposite-lyingfront surfaces 56 are shaped such that they form a labyrinth seal. Forthis, the opposite-lying front surfaces 56 of neighboring coils 30 havefor example a tongue and groove connection. Any other shape of the frontsurfaces 56 is conceivable, which fulfills the purpose of a labyrinthseal, for example a complementary shape of opposite-lying front surfaces56.

According to the invention, the wire thread insert 1 comprises afastening flange 40 on one end of the cylindrical spiral 20. Thefastening flange 40 projects radially outwards over the spiral wall 22,24 of the cylindrical spiral 20, as can be seen in FIGS. 1, 2 and 9. Thefastening flange 40 is preferably formed by at least one coil 42. Thecoil 42 is wound with reduced or without slope compared to the othercoils 30 of the spiral 20 on the end of the cylindrical spiral 20 (S2)so that the coil(s) 42 of the fastening flange 40 have a reduced and/orno slope compared to the slope of the spirals 20. On this constructivefoundation, the fastening flange 40 comprises at least two coils 42lying above each other in the radial direction of the cylindrical spiral20. The radially outer coil 42 of the fastening flange 40 is designed atleast partially, preferably completely, circumferentially around thespiral 20. Depending on the component material in which the fasteningflange 40 should fasten the wire thread insert 1, the number of coils 42lying above each other is selectable.

In accordance with a further preferred embodiment of the fasteningflange 40, it has a first coil 42, which is connected to the end 28 ofthe cylindrical spiral 20 (see FIG. 7). The first coil 42 extends alonga circumferential segment of the fastening flange 40, which extends overa certain angle γ (see FIG. 7). The angle γ has a minimum size of 180°,so that the first coil 42 in the shape of the circumferential segmentextends around half of the cylindrical spiral 20 as seen in thecircumferential direction. In another design of this embodiment, thecircumferential segment of the first coil is designed larger so that itextends over an angle γ of 180° to 270° and more preferably of 180° to360°. A further embodiment of the fastening flange 40 comprises acomplete first coil 42. This means that the first coil 42 extends over acircumferential segment of the fastening flange 40 with an angle γ=360°starting at end 28 of the cylindrical spiral 20. A second coil 42connecting to the first coil 42 also extends along a circumferentialsegment of the fastening flange 40. The circumferential segment of thesecond coil 42 starts at end 29 of the first coil 42 (FIG. 7). Thecircumferential segment of the second coil also extends over the angleγ, which is greater than 180°. The angle γ preferably comprises 180° to270° and more preferably 180° to 360°.

In accordance with a further conceivable alternative, the fasteningflange 40 extends over several coils 30 of the cylindrical spiral 20. Inthis case, the slope of the coils 42 of the fastening flange 40 isopposite the slope of the cylindrical spiral 20. It is also preferredthat the fastening flange 40 merges into a fastening spiral (not shown),which extends over a part or the entire length of the cylindrical spiral20. Preferably, neighboring coils of the fastening spiral do not lieagainst each other so that component material can get in between andensures an additional fastening of the wire thread insert 1 in thecomponent.

Due to its shape, the fastening flange 40 forms a contact surface 44,which is arranged perpendicular to the center axis of the cylindricalspiral 20 (see FIG. 2). Based on this geometry, it is no longer requiredto grind off the front side of the wire thread insert 1 with fasteningflange 40 in order to create an even contact surface, for example in amold 90 for component production. The contact surface 44 makes it easierfor a worker to seal the front side of the wire thread insert duringcomponent production. The fastening flange 40 also serves as apositioning aid when it is mounted on a pin 92 of a mold 90 forcomponent production (step B, see FIGS. 8, 9, 11). In its installedstate, the fastening flange 40 has the further advantage that radialtensions, which occur through the screwing in and tightening of a screwin the wire thread insert 1, are shifted further in the direction of thecylindrical spiral 20 and thus into the component. In this manner, thecritical overlapping of compression stresses, for example through ascrew-on part on the component and the radial tensions on the threadflanks of the wire thread insert 1, is reduced. Furthermore, thefastening flange 40 advantageously serves as a constructive supportduring mounting and insertion of a fastening element into the wirethread insert 1 molded into the component. Furthermore, the fasteningflange 40 represents a unique sorting criterion based on its largerdiameter compared to the cylindrical spiral 20, with the help of whichautomated handling of the wire thread insert 1, for example duringassembly of the mold 90 for component production, is facilitated.

In accordance with a further preferred embodiment, a fastening flange 40is provided on each respective end of the cylindrical spiral 20. Thispreferred embodiment is shown in FIG. 7 in a perspective view as well asin FIG. 8 in a perspective cut representation. Coils 42, which form thefastening flange 40 are arranged respectively on both ends of thecylindrical spiral 20 with closed spiral wall. The coils 42 of thefastening flange are also arranged radially outwards compared to theclosed spiral wall.

While the production of the moldable wire thread insert 1, mechanicaltensions are imprinted into the wire 10 in the axial direction of thewire thread insert 1, which work against each other to cause a pullingtogether of the coils 30, 42. In this manner, neighboring coils 30 and42 are adjacent to each other in order to seal the interior of themoldable wire thread insert 1 from its environment. This pullingtogether and adjacency of neighboring coils 30, 42 are also detectiblein the perspective cut representation in FIG. 8. While the axial frontsides 56 of the coils 30 are preferably adjacent to each other in thearea of the cylindrical spiral 20, the flanks of the thread area 52partially lie against the flanks of the anchoring area 54 in the area ofthe fastening flange 40. Even if the flanks of the thread area 52 andthe anchoring area 54 are only adjacent at selected points, the coils 42of the fastening flange 40 are arranged such that they form a labyrinthseal. This labyrinth seal prevents a penetration of material, forexample plastic, into the interior of the moldable wire thread insert.This applies in the same way for wire thread inserts 1 with one or twofastening flanges 40.

In accordance with a further preferred embodiment, the cylindricalspiral 20 of the moldable wire thread insert 1 comprises at least onecoil 38, which serves as a securing device for a screw screwed into thewire thread insert 1 (not shown). It is also preferred to provide aplurality of these coils 38. As can be seen in FIG. 9, the coil 38constricts the inner diameter of the cylindrical spiral 20 in asecant-like manner. Although clamping torques for a screw to be screwedinto the wire thread insert 1 (not shown) need to be achieved, it mustalso be ensured that no separation distances occur between neighboringcoils 38 and 30 of the cylindrical spiral 20, which enable a penetrationof material, such as e.g. plastic, into the interior of the moldablewire thread insert 1. The smallest diameter, which is formed by a coil38, is thus calculated according to the following formula. It is equalto a core diameter of the internal thread to be formed by the wirethread insert 1 minus a tenth of the nominal diameter of the internalthread to be formed by the wire thread insert 1. When taking thisformula into consideration, it is preferably ensured that both asufficient clamping of a screw to be screwed in is given and apenetration of a material, into which the wire thread insert 1 ismolded, is prevented. A side view of the moldable wire thread insert 1with coil 38 is shown in FIG. 10.

The moldable wire thread insert 1 of the present invention comprisesalternatively or supplementarily to the fastening flange 40 one end ofthe cylindrical spiral 20, which is designed in a planar manner. Thisend of the cylindrical spiral designed in a planar manner forms an evenaxial front surface of the cylindrical spiral and thus of the wirethread insert 1, in order to support for example a positioning of thewire thread insert 1. A corresponding wire thread insert 1 withoutfastening flange 40 is shown in FIG. 3. The last coil 30 on one or bothends of the cylindrical spiral 20 is designed in a planar manner so thatthe contact surface 36. During the production of the wire thread insert1, the contact surface 36 is created through the grinding off ofindividual wire thread inserts 1 or through the cutoff grinding of theendless wire thread insert 3 (S5, see FIG. 7).

For the preferred fastening of the wire thread insert 1 in the componentmaterial, the radial outer wall 24 of the cylindrical spiral 20comprises at least one groove 26 running in the longitudinal directionof the cylindrical spiral 20. A plurality of such grooves 26 arepreferably provided on the radial outside 24. An example of such agroove 26 is shown in FIG. 6. In the case of component production withmoldable wire thread insert 1, the component material penetrates intothe groove 26 and in this manner forms an undercut, which stabilizes thewire thread insert against possible twisting. Any shapes that fulfillthis function are conceivable for the groove 26. Thus, the groove is forexample angular, slotted or similarly shaped. In accordance with FIG. 6,the groove 26 runs in a straight line in the axial direction of thespiral 20. It is also preferred to provide a curvilinear progression ofthe groove 26. The groove 26 also runs in an interrupted line orconsists of segments offset laterally with respect to each other.

Depending on the component material, the cross-section 50 of the wire 10or respectively of the coils 30 of the cylindrical spiral 20 issymmetrically (see FIG. 5) or asymmetrically shaped (see FIGS. 3 and 4).In the case of a symmetrical cross-section 50, the thread area 52 andthe anchoring area 54 have the same shape. In the case of anasymmetrical cross-section 50, the shapes of thread area 52 andanchoring area 54 are different. The anchoring area 54 is preferablydesigned in an acute-angled manner so that the anchoring area 54penetrates as far as possible into the component material. In thismanner, the wire thread insert 1 forms a larger thrust cylinder comparedto the symmetrical cross-section 50 of the coils 30, whereby the pulloutstability of the wire thread insert out of the component material isincreased. In order to realize this advantage, the two flanks of theanchoring area 54 preferably form an angle α<60°. In this connection, itis further preferred that the angle α has a size of 30° through 40°.

In accordance with a further preferred embodiment, the wire threadinsert 1 on its end facing away from the fastening flange 40 comprises atang 34 penetrating radially into the spiral 20, as shown in FIG. 9.During the production of the component, the tang 34 preferably serves asa depth stop of the wire thread insert 1 on the pin 92 of the mold 90(see FIG. 14). The wire thread insert 1 is thereby mounted on the pin 92and holds its position on the pin 92 and thus in the mold 90 due to tang34. During filling of the mold 90 with component material (step D), thetang 34 is also enclosed. After the hardening of the component material,the surrounded tang 34 contributes to the further stabilization andfastening of the wire thread insert 1 in the component.

It is also preferred to forgo the tang 34 or to remove the tang 34 afterthe molding of the wire thread insert 1 into a component so that thewire thread insert 1 has a free through hole opening on its end facingaway from the fastening flange 40. This free through hole opening issignificant when the wire thread insert 1 reinforces a through hole inthe component. In this case, a screw can protrude out for the fasteningof an addon part after the screwing into the through hole on the throughhole opening of the wire thread insert 1.

For the production of the wire thread insert, a winding spindle 70 ispreferably used, as is shown in FIG. 12. The winding spindle 12comprises a first cylindrical area 72 as well as a second area 74radially expanded in comparison to the cylindrical area 72. Inaccordance with FIG. 12, the end of the first area 72 facing the secondexpanded area 74 preferably has a notch 76. This notch 76 serves toreceive the end of the wire 10 to be wound in order to form the alreadyaforementioned radially inwards projecting pin 34.

Within the second area 74, the winding spindle 70 expands out of thefirst area 72 radially outwards. This expansion preferably takes placealong a surface continuously or gradually. FIG. 12 shows a gradualexpansion, in which thread-like depressions are worked into the secondexpanded area 74, too. The expanded area 74 has an outer surface similarto the shell surface of a cone, which is arranged at a certain angle αto the longitudinal axis L of the winding spindle. The angle α assumesvalues in the area of 90° to 140°, preferably 100° to 120°. Inaccordance with a preferred embodiment, the angle is α=90°. In thiscase, the second area 74 is formed through a ledge compared to the firstcylindrical area 72, which is indicated in its mold by the dashed linein FIG. 12.

For the production of the fastening flange 40, an angle α>90° ispreferred in order to make the second expanded area 74 available for thewinding spindle 70. During the production of the moldable wire threadinsert 1, the wire 10 is preferably fed perpendicular to thelongitudinal axis L in the direction of the wire feed direction DZ (seeFIG. 12) to the winding spindle 70. In the case shown schematically inFIG. 12, the wire 10 is fed to the winding spindle 70 at an angle β=90°to the longitudinal axis L. It is also preferred to include an angle βgreater or less than 90° between the wire feed direction DZ and thelongitudinal axis L of the winding spindle in the winding direction ofthe wire thread insert 1—i.e. from the first area 72 to the second area74. It is ensured with the help of this alignment of the feed directionDZ to the longitudinal axis L of the winding spindle 70 that mechanicaltensions are molded or respectively embossed into the wire 10 of thewire thread insert 1 during the winding of the moldable wire threadinsert 1 in a targeted manner.

During the winding of the moldable wire thread insert 1, the windingspindle 70 is shifted in the advance direction V (see arrow in FIG. 12)relative to the wire 10 or respectively its feed position in the wirefeed direction DZ. It is also conceivable that only the wire 10 isshifted relative to the longitudinal axis L of the winding spindle 70 orthat both the winding spindle 70 as well as the wire 10 aresimultaneously shifted relative to each other in order to wind themoldable wire thread insert 1.

A preferred embodiment of the production of the wire thread insert 1 isshown in the flow chart in FIG. 15. The wire is thereby preferably madeof a light metals or steel or stainless steel or copper or brass. Whilemetals with corrosion protection are preferred, it is also conceivableto not use corrosion-protected metals. Wires 10 without corrosionprotection to which corrosion protection is applied after the windingcan also be used.

The moldable wire thread insert 1 is preferably produced with the helpof the winding spindle 70 already described above (see FIG. 12). In afirst preferred step S1, the endless wire 10 is fastened in the notch 76of the winding spindle 70 in order to form the radially inward stickingtang 34. After this, the winding of the wire 10 to the cylindricalspiral 20 begins along the first cylindrical area 72 of the windingspindle 70 (step S2). For this purpose, the first cylindrical area 72 ofthe winding spindle 70 comprises a thread, which specifies mainly thelater shape of the inner thread of the moldable wire thread insert 1.The cylindrical spiral 20 is shaped on the first cylindrical area 72with a certain diameter according to the planned thread of the wirethread insert 1. In addition to the diameter, the coils 30 of thecylindrical spiral 20 also have a first slope, which is specified by thethread on the first cylindrical area 72.

After the cylindrical spiral 20 has been wound onto the firstcylindrical area 72, the wire 10 is wound on or against the secondexpanded area 74 of the winding spindle 70. In this manner, thefastening flange 40 projecting radially outwards over the spiral wall22, 24 is created on one end of the spiral 20 (step S3A). Alternativelyto the creation of a fastening flange, it is also preferred tosurface-grind the cylindrical spiral 20 on at least one end, preferablyin that the cylindrical spiral is separated into at least two partsthrough cutoff grinding (step S3B). This process is explained in greaterdetail below.

In accordance with a first embodiment, the fastening flange 40 isproduced with the help of the winding spindle 70, which has the secondexpanded area 74 in the shape shown in FIG. 12. The wire 10 is wound onthe second area 74 in order to form the coils 42 of the fastening flange40. Compared to the coils 30 of the cylindrical spiral 20, the at leastone coil 42 of the fastening flange 40 wound on the area 74 has a lesserslope and a greater diameter. The wire 10 is preferably wound onto thesecond expanded area 74 of the winding spindle 70 such that after acutting of the wire 30 off of the wound wire thread insert 1, preferablythrough a stamping process, and the unspindling (step S5) of the wirethread insert 1 from the winding spindle 70 the end of the spiral 20 hasthe fastening flange 40 described above. The fastening flange 40comprises at least one coil 42 extending in the radial direction overthe cylindrical spiral 20, which runs along a circumferential segmentwith an angle γ. The fastening flange 40 preferably comprises two coils42 lying above each other in the radial direction. It is furthermorepreferred that the radially outer coil 42 of the fastening flange 40extends along a circumferential segment with the angle γ<360° subsequentto the first coil 42 of the fastening flange 40. It is also preferred tocreate one or two coils 42 of the fastening flange 40, which extend overa certain circumferential segment as described above.

In order to wind the wire thread insert 1, the winding spindle 70 ispreferably moved in the advance direction V (see FIG. 12). Meanwhile,the feed position of the wire 10 with feed direction DZ remainsconstant. The feed or offset V of the winding spindle 70 is setdepending on the slope of the thread to be wound on the cylindrical area72.

During the winding of the wire thread insert 1, the wire 10 ispreferably fed at an angle β to the longitudinal axis L of the windingspindle 70 (see FIG. 12). The angle β is formed by the wire feeddirection DZ and the longitudinal axis L of the winding spindle 70 inthe winding direction of the wire thread insert—i.e. against the advancedirection V of the winding spindle 70. The angle β is preferably ≧90° inorder to emboss mechanical stress into the wire 10 of the wire threadinsert. This mechanical stress in the wire 10 of the wire thread insert1 ensures that neighboring coils 30, 42 are adjacent to each other afterthe unspindling of the wire thread insert 1 from the winding spindle 70.In this manner, a wire thread insert 1 wound on a block is provided, theinterior of which is sealed from penetration of for example plastic fromthe outside during production of a component and molding of the wirethread insert.

Moreover, the wire 10 is preferably supplied with a tensile strength inits longitudinal direction during the winding of the wire thread insert1 so that deformations of the wire 10 can be created outside the elasticarea. This procedure ensures that a moldable wire thread insert 1 woundon a block is also present after the unspindling of the wire threadinsert from the winding spindle 70.

The cylindrical spiral 20 of the completed wire thread insert 1 shouldprovide an internal thread with a nominal slope. In order to achievethis, the thread 73 of the first area 72 of the winding spindle 70 ispreferably designed with an overslope. In this case, an overslope meansthat the slope of the thread 73 is greater than the nominal slope of theinternal thread of the later cylindrical spiral 20. If one assumes basedon FIG. 12 a constant, vertical feed position of the wire 10 duringwinding of the cylindrical spiral 20 on the thread 73, the windingspindle 70 is moved by a certain amount in the axial advance direction Vper revolution during the winding of the cylindrical spiral 20. If theslope of thread 73 matches the nominal slope of the later cylindricalspiral 20, the winding spindle 70 is preferably moved in the advancedirection V per revolution with winding spindle with the nominal slope.

In accordance with another preferred alternative, in which the thread 73has the over slope discussed above, the winding spindle 70 is moved inthe case of a constant wire feed position in advance direction V by anamount smaller than the over slope of the thread 73 per revolution. Thisamount corresponds for example to the nominal slope of the thread of thelater cylindrical spiral 20. Due to this advancement or respectivelyoffset of the winding spindle 70 in the axial direction per revolution,the wire 10 is fed at an angle β>90° (see FIG. 12) to the first area 72of the winding spindle 70. This combined forcible guiding of the wire 10through the thread 73, the axial advancement of the winding spindle 70and the resulting angle β embosses the inner mechanical tensiondescribed above into the moldable wire thread insert 1.

The one or more coils 42 of the fastening flange 40 are preferablycreated with the help of the second area 74 of the winding spindle 70,which has the thread 75. In accordance with another preferred process,the thread 75 is designed with an under-slope compared to the nominalslope of the internal thread of the later cylindrical spiral 20. In thiscase, under-slope means that the slope of the thread 75 is less than thenominal slope of the cylindrical spiral 20. If the wire 10 is wound ontothe second area 74 of the winding spindle 70 in the case of the constantfeed position in the feed direction DZ onto the second area 74, thewinding spindle 70 is moved in the advance direction per revolution by acertain amount. This amount is preferably less than the under slope ofthe thread 75 so that mechanical tensions are embossed into the wirethread insert 1 in a similar manner, as described above. This embossedmechanical tension ensures that the one or more coils 42 of thefastening flange 40 are arranged in almost one plane at the end of thecylindrical spiral 20 after the completion of the wire thread insert 1.

It is also conceivable to change the feed position of the wire 10 withrespect to the winding spindle 70 in the feed direction V while thewinding spindle 70 retains its axial position.

According to another preferred alternative of the present productionmethod, the second area 74 of the winding spindle 70 has a ledge againstwhich the wire 10 is wound. As soon as the wire 10 is wound against theledge 74 (see FIG. 12), the coils 42 of the fastening flange 40 arrangethemselves next to each other with partial overlapping in order to formthe fastening flange 40.

It is furthermore preferred to create groove 26 running in the axialdirection on a radial outside of the spiral 20 after the winding of thewire 10 onto the winding spindle 70. In accordance with one alternative,this is realized by means of milling.

The wire thread insert 1 is then unspindled from the winding spindle 70(S5). After the unspindling, the neighboring coils 30, 42 lie adjacentsuch that a wire thread insert 1 wound on a block is present. In thismanner, a regular thread is preferably formed on the inside of the wirethread insert 1, which is sealed towards the outside. It is alsopreferred to form a special thread on the inside, such as for example afine thread, a trapezoidal thread, a course thread or the like.

In accordance with another alternative, one end of the cylindrical spool20 is surface-ground instead of or in addition to the fastening flange40 (see step S3B). In order to realize this, an endless wire threadinsert 3 is first wound on a mandrel 100 in accordance with a productionroute (see FIG. 11). The pin 100 is designed for example in two parts sothat a passage can be formed between the two neighboring parts of themandrel 100. A cutoff wheel 105 is then moved by the penetration of thetwo mandrel parts 100 and in this way separates the wire thread insert 3into two parts in the arrow direction of the left illustration in FIG.7. Once the cutoff wheel 105 has returned to its initial position inaccordance with the right illustration in FIG. 7 (see arrow), two wirethread inserts 1 each with planar end 36 are present.

The production method for producing a component with molded wire threadinsert 1 is explained in greater detail with respect to the flow chartin FIG. 11 and the illustration in FIGS. 8 and 9. The component (notshown) is for example made of plastic through injection molding or ofmetal through a suitable casting process. Other production processes arealso suitable for a component with which the wire thread insert 1 ismoldable.

A mold 90 consisting of the two mold halves 94 and 96 for the productionof a component with molded wire thread insert 1 is shown as an examplein FIGS. 13 and 14. The mold half 94 comprises the pin 92, on which thewire thread insert 1 is positioned (steps A, B). In accordance with afirst preferred alternative, the wire thread insert 1 is mounted on thepin 92 and glides on the surface of the pin 92 until it rests on acontact surface. For this purpose, the pin 92 has no thread (step B). Inaccordance with a further alternative, the wire thread insert 1 isscrewed or spindled onto the pin 92 since it has on its outside anexternal thread fitting the internal thread of the wire thread insert 1(step A).

FIG. 13 shows that the wire thread insert 1 should reinforce a throughhole opening in the component. Once the component material has beenadded to the mold 90 so that it fills in the hollow spaces between themold halves 94 and 96, the component material hardens. After the step offilling the mold (D) and the hardening of the component material, thecomponent is removed from the mold 90 in step E.

In the production alternative shown in FIG. 14, the wire thread insert 1supports itself via tang 34 on pin 92 of mold 90. After filling the mold90 with for example metal or plastic, the component material hardens sothat the wire thread insert 1 reinforces an opening in the componentthat is closed on one side.

In FIGS. 13 and 14, it is also conceivable that either the contactsurface 36 or the fastening flange 40 guarantees that on one side thewire thread insert 1 ends adjacent to a component surface, the wirethread insert 1 in the mold 90 is precisely positioned and an additionalsealing of the inside of the wire thread insert 1 also takes placeadjacent to the mold half 94.

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 31. A moldable wire thread insert forreinforcing a screw-in opening of a component, said insert comprising:a) a cylindrical spiral made of a helically, wound wire, b) said spiralhaving neighboring coils arranged such that a closed cylindrical spiralwall is present, c) at least one end of the cylindrical spiral having afastening flange, said fastening flange extending radially outwards overthe cylindrical spiral wall and with which the wire thread insert isanchorable in the component, whereby the fastening flange comprises atleast one flange coil of the wound wire, which has a reduced slopecompared to the remainder of the cylindrical spiral.
 32. The wire threadinsert according to claim 31, further comprising a first coil extendingalong a circumferential segment of the fastening flange starting at theend of the cylindrical spiral over an angle γ of at least 180°.
 33. Thewire thread insert according to claim 32, further comprising a completefirst coil and a second coil, which extends along a circumferentialsegment of the fastening flange starting at the end of the first coilover an angle γ of at least 180°.
 34. The wire thread insert accordingto claim 31, in which said fastening flange comprises at least two coilsof the wound wire lying above each other in the radial direction of thecylindrical spiral, wherein a radially outer coil of the fasteningflange is designed circumferentially at least partially, around thespiral.
 35. The wire thread insert according to claim 31, wherein thecylindrical spiral wall includes at least one groove running in thelongitudinal direction of the outer radial wall of the cylindricalspiral.
 36. The wire thread insert according to claim 31, in which thewire has a cross-section shaped such that the inner radial wall of theclosed cylindrical spiral wall has a standard thread.
 37. The wirethread insert according to claim 31, in which a cross-sectional profileof the wire has an angle contour with two flanks radially outwards withrespect to the cylindrical spiral, which form an angle α<60°.
 38. Thewire thread insert according to claim 37, in which the cross-section ofthe wire is designed asymmetrically with respect to the inner and outerradial walls of the cylindrical spiral.
 39. The wire thread insertaccording to claim 31, the end of the cylindrical spiral has one of aninwardly radially protruding tang and a free through hole opening acrossfrom the end having the fastening flange.
 40. The wire thread insertaccording to claim 31, in which a cross-section of the wire has frontsurfaces in the axial direction of the spiral such that front surfacesof neighboring coils are adjacent to each other.
 41. The wire threadinsert according to claim 40, in which the front surfaces of neighboringcoils are complementarily shaped to each other.
 42. The wire threadinsert according to claim 31, in which said insert consists of at leastone of the group consisting of a light metal alloy, steel, stainlesssteel, copper and brass.
 43. A component made of plastic or metal, inwhich a wire thread insert is molded according to claim
 31. 44. Aproduction method for a moldable wire thread insert for reinforcing ascrew-in opening of a component, said method comprising the steps of: a)winding a wire into a cylindrical spiral with a diameter such thatneighboring coils of the cylindrical spiral have a first slope and forma cylindrical spiral wall, b) creating a fastening flange protrudingradially outwards over the spiral wall on at least one end of the spiralthrough winding of at least one coil of the spiral on one end of thespiral with a reduced slope compared to the first slope, in order tocreate the fastening flange.
 45. The production method according toclaim 44, which further comprises the step of: winding the fasteningflange such that the fastening flange has a greater diameter than thespiral, wherein the end of the spiral comprises at least two coils ofthe wound wire lying above each other in the radial direction of thecylindrical spiral.
 46. The production method according to claim 44,comprising the further step of: winding the wire onto a winding spindle,wherein the winding spindle comprises a first cylindrical area forwinding the cylindrical spiral and a second area extended in the radialdirection compared to the first cylindrical area for winding thefastening flange.
 47. The production method according to claim 46,comprising the further step of: winding the fastening flange such thatthe wire is wound on the second extended area of the winding spindle,which extends constantly or gradually, or such that the wire is woundagainst the second extended area, which represents a ledge compared tothe first cylindrical area.
 48. The production method according to claim46, comprising the further step of: winding the wire onto the windingspindle such that a longitudinal axis of the winding spindle in theangle direction of the wire thread insert and a wire feed direction ofthe wire to be wound form an angle β>90°.
 49. The production methodaccording to claim 46, comprising the further step of: offsetting thewinding spindle and the wire to be fed relative to each other withdifferent speeds during the winding of the wire onto the first and thesecond area of the winding spindle.
 50. The production method accordingto claim 44, comprising the further step of: unspindling the cylindricalspiral with fastening flange from a winding spindle such thatneighboring windings of the spiral and the fastening flange rest againsteach other in a sealing manner.
 51. The production method according toclaim 44, comprising the further step of: hooking the wire to be woundinto a notch of the winding spindle and creating a radially inwardssticking tang on the end of the spiral facing away from the flange ontothe winding spindle through the winding up of the wire.
 52. Theproduction method according to claim 44, comprising the further step of:creating at least one groove running in the axial direction on a radialouter wall of the spiral by means of milling.
 53. A production methodfor a component with a molded wire thread insert, said insert comprisinga cylindrical spiral formed from a helically wound wire, of which atleast one end comprises a fastening flange extending radially outwardsover the cylindrical spiral, wherein the component is made of plastic ormetal and the method comprises the steps of: a) positioning the wirethread insert on a pin, b) arranging the pin with the positioned wirethread insert in a mold such that, after demolding of the component fromthe mold, the fastening flange is arranged adjacent to a componentsurface, c) filling the mold with metal or plastic, and d) demolding thecomponent with the wire thread insert from the mold.
 54. The productionmethod of a component according to claim 53, in which said positioningstep a) includes a further step of either: spindling the wire threadinsert onto said pin, said pin having a thread fitting the wire threadinsert, or mounting of the wire thread insert onto a pin without thread.55. The production of a component according to claim 53, in which saidfilling step c) includes the further step of: injection molding ofplastic in the mold for producing the component.
 56. A winding spindlefor winding a moldable wire thread insert, said spindle comprising: a) afirst cylindrical area with a thread and b) a second area, which isexpanded in the radial direction compared to the first area so that afastening flange of the moldable wire thread insert is producible withthe help of the second area.
 57. The winding spindle according to claim56, in which the second expanded area is constantly or graduallyexpanded compared to the first cylindrical area.
 58. The winding spindleaccording to claim 56, in which the second expanded area is designed asa single level and represents a ledge compared to the first cylindricalarea.
 59. The winding spindle according to claim 56, further including anotch on one end of the first cylindrical area, in which a wire to bewound is fastenable in order to form a radially inward sticking tangduring the winding of the wire thread insert.
 60. The winding spindleaccording to claim 56, in which the second area is arranged at an angleof 90° to 120° relative to the longitudinal axis of the winding spindle.